This invention relates to an anti-theft device for a vehicular electric apparatus such as an audio apparatus.
There is available an anti-theft device for a vehicular audio apparatus. The device is so designed that the audio apparatus can operate only after a user inputs a predetermined code by operating keys on the device each time the audic apparatus as a whole is connected to a power source. That is, even if the audio apparatus stolen is connected to a power source, it will not operate since the thief or a third person does not know the code.
However, this type of anti-theft device is useless in the case where the audio apparatus is stolen with the power source connected to it.
On the other hand, the power source is generally a vehicle battery. The battery is usually kept connected to a vehicular electric apparatus as long as the electric apparatus works normally and the battery is within its a service life. When the battery is replaced because of termination of its service life, it is necessary to input the code to make the electric apparatus operational. If the inputting of the code has not been carried out for many years, then the code may be forgotten, resulting in a problem that the electric apparatus cannot operate.